Automobile engine air filtration systems suffer from a finite and moderate dust-holding capacity. Higher dust capacities are required when driving under severe dusty driving conditions. Furthermore, engine air filters may be ill-equipped to deal with water, snow, salt, or large contaminants. In other applications, such as process industries or engines for other vehicles, pre-separator devices are sometimes used to improve the contaminant removing capacity of the filtration system. Under heavy conditions, a pre-separator may extend the life of the air cleaner filter by three to five times its normal life span.
A cyclone-type separator is typically employed because of its high capacity and efficiency for removing contaminants. A blower, compressor, or pump forces the gas tangentially into a tapered tube, thereby creating a spinning vortex. The centrifugal force created by the vortex separates particles from the stream of gas, as the gas accelerates as it is forced through the tapered tube. The contaminants are forced from the center of the stream to the walls of the tube, and are collected in a chamber for removal. An outlet tube is positioned within the center of the tapered tube, and clean air is sucked from the center of the vortex.
While typical cyclone separators achieve a high particle separation efficiency, these separators suffer significant drawbacks which limit their use with automotive engine applications. First, there is a significant energy requirement to create this vortex and withdraw the clean air, which in turn burdens the engine and reduces horsepower. Further, the high flow velocity along the large inner surface area of the tube creates a large pressure drop and corresponding head loss, also resulting in reduced horsepower. Additionally, the tapered tube necessary to create the centrifugal forces is too large for the already restricted confines of the engine bay. Finally, the cyclone separator must be positioned in a vertical orientation for proper operation, further limiting its ability to be included in the filtration system for an automotive engine.
Accordingly, there exists a need to provide a pre-separator that can be easily packaged as a part of the filtration system for an automotive engine, while providing the requisite contamination separation efficiency without significant horsepower loss to the engine.
While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.